Ubuntu切換bash腳本

1.Ubuntu預設的dash帶來的問題

#文法錯誤問題
free.sh: 3: free.sh: Syntax error: "(" unexpected
           

#檢視到/bin/sh是軟連結dash
ls -lh /bin/*sh
-rwxr-xr-x 1 root root 1.1M Jun  6  2019 /bin/bash
-rwxr-xr-x 1 root root 119K Jan 25  2018 /bin/dash
lrwxrwxrwx 1 root root    4 Jun  6  2019 /bin/rbash -> bash
lrwxrwxrwx 1 root root    4 Feb  9 09:38 /bin/sh -> dash
lrwxrwxrwx 1 root root    7 Mar  6  2019 /bin/static-sh -> busybox
           

2.切換bash腳本